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ANTH-001
Question
Response
General
AOAC Method Number:
ANTH-001
Method Title:
Determination of Anthocyanins in Brazilian and Floridian
Açaí (Euterpe oleraceae Mart) Using LC-MS/MS
Method Author(s):
Tran et al.
Reviewer Name:
Jungmin Lee
Summary of Method
Describes quantitative Acai anthocyanin analysis.
Method Scope / Applicability:
Could be relevant to Acai anthocyanin analysis.
General Comments About the
Method:
Authors did not demonstrate that their method is capable of
separating Vaccinium fruit anthocyanins.
Method Clarity
Protocol is too ambiguous. Authors used term
‘anthocyanidins’ incorrectly. Mass to charge ratios for the 2
anthocyanins are incorrect in Figures 2 and 3 (Mother ions >
daughter ions of cyanidin-glucoside- 449 > 287 and cyanidin-
rutinoside, 595 > 449 > 287). There are inaccuracies with
their peak identifications. Cyanidin-glucoside typically elutes
before cyanidin-rutinoside under similar HPLC conditions, in
addition to the mix up in anthocyanin m/z (mass to charge)
results and labeling in both Figs 2 and 3. Euterpe oleracea
contains cyanidin-sambubioside (581 > 287), cyanidin-
glucoside (449 > 287), cyanidin-rutinoside (595 > 449 > 287),
and peonidin-rutinoside (609>301) (in the order of HPLC
elution; Schauss et al. 2006 JAFC 54:8598-8603; slightly
different in minor peaks according to Heinrich et al. 2011.
Phytochem 4:10-21). Cyanidin-rutinoside will elute after
cyanidin-glucoside (in opposite order to what authors report
here). Again, authors did not identify acai anthocyanins
correctly.
Pros/Strengths
Could have ability to qualitatively and quantitatively analyze
2 anthocyanins, but incorrect cyanidin-glucoside and
cyanidin-rutinoside identification is highly suspect.
Cons/Weaknesses
Method must prove that the peaks of a complex
anthocyanin mixture can be sufficiently separated.